相位梯度自聚焦算法在条带模式SAR中的应用

相位梯度自聚焦(PGA)算法是一种稳健的高分辨SAR相位校正方法，在SAR领域得到广泛应用。但PGA是对聚束模式成像提出的，不能直接用于条带模式。本文利用两种模式之间的内在联系，将条带模式SAR数据分块处理，等效成聚束模式数据。然后，用聚束照射SAR成保算法实现成像，此时就可以利用PGA完成各决于图像的自聚焦过程，最后将各于固体适当拼揍，从而实现条带模式SAR的PGA处理，外场数据的处理证实了本文方法的可行性，同时，分块处理条带SAR数据实现了聚束照射SAR与条带模式SAR成像算法上的统一。

Phase Gradient Autofocus Algorithm for Stripmap SAR Autofocus

The phase gradient autofocus (PGA) algorithm, used in SAR community is proven to be a superior phase error correction method for fine resolution SAR. The PGA technique for spotlight mode imaging, however, cannot be directly applied to image formed in the stripmap mode. Based on the inherent relation between spotlight mode SAR and stripmap mode SAR, a modified approach is presented. Firstly, the stripmap data are provided to several segments equivalent to spotlight data. Next, sub-image formation is performed by spotlight imaging algorithm. At this point, PGA can be used on sub-images to improve image quality. Finally the subimages are logically mosaiced and stripmap mode PGA is accomplished. The processing results of live data show the method. Additionally, subpatch processing to stripmap SAR data realizes the unification of spotlight and stripmap SAR image formation algorithm.